if it takes 31,500 joules of heat to warm 750g of water, what was the temperature change?

My answer:

Q = (M) (DeltaT) (c)
Delta T=Q
Delta T = 31,500J
--------
750gx 1.0cal/gCo

Delta T = 42oC

3 answers

1 calorie/gram °C = 4.186 joule/gram °C

you should use 4.186J/g°C not 1.0 cal since the conversion is using grams and energy (J)
If you change that and repost, someone will check it.
You have to multiply it by the specific temperature of water